Larger bone graft size and washing of bone grafts prior to impaction enhances the initial stability of cemented cups: Experiments using a synthetic acetabular model

Figures & data

Figure 1. Synthetic acetabular model with a reconstructed combined defect.

Table 1. Properties of the test group.

Model code	n	Bone graft size (mm)	Additional preparation
LW	5	Large (8–12)	Pulse lavage washing
LU	5	Large (8–12)	None
SW	5	Small (2–4)	Pulse lavage washing
SU	5	Small (2–4)	None

Figure 2. Loading schedule during the mechanical compression test.Three loading periods were applied of 15 min each.First a dynamic load ranging from 0 N to 1,500 N was applied.Subsequently the model was loaded with a dynamic load ranging from 0 N to 3,000 N after it remained unloaded (0 N) during the last 15 min.

Figure 3. Overview of the lever-out test facility. The acetabulum model is confined in the holder. A metal rod is fixated in the acetabular cup and connected to the MTS machine (arrow) by a pulley.

Figure 4. Two-dimensional representation of cup with cement layer on top.

Figure 5. Mean cup displacement (mm) during loading and subsequent unloading, using linear mixed model analysis. SW: small, washed bone grafts; SU: small, unwashed bone grafts; LU: large, unwashed bone grafts; LW: large, washed bone grafts.

Table 2. Mean lever-out moment values (SD) at model failure, and depth of cement penetration

Group	LW	LU	SW	SU
Moment (Nm)	11.5 (7.42)	4.13 (2.65)	2.39 (0.52)	1.80 (0.53)
Cement penetration (mm)	1.41 (0.33)	1.39 (0.32)	0.98 (0.20)	0.92 (0.18)

Abbreviations, see Figure 5.